A wideband analog correlator for microwave background observations

Padin, S.; Cartwright, J. K.; Shepherd, M. C.; Yamasaki, Jorge; Holzapfel, W. L.

doi:10.1109/19.963190

Cited by 19 publications

(24 citation statements)

References 9 publications

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“…Each receiver IF is further split and downconverted to ten 1 GHz-wide bands centered at 1.5 GHz. An analog correlator (Padin et al 2001b) processes the 1 GHz bands into 780 complex visibilities.…”

Section: Instrumentmentioning

confidence: 99%

“…Additional parameters, such as the baryonic matter density ( b h 2 ), can be extracted by resolving the higher order peaks in the power spectrum. Hints of structure appear to be present in some smaller angular scale CMB power spectra (Hanany et al 2000;Padin et al 2001a), but there has been no clear detection of the predicted higher order acoustic peaks.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Degree Angular Scale Interferometer First Results: A Measurement of the Cosmic Microwave Background Angular Power Spectrum

Halverson

Leitch

Pryke

et al. 2002

ApJ

Self Cite

669

331

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We present measurements of anisotropy in the cosmic microwave background (CMB) from the first season of observations with the Degree Angular Scale Interferometer (DASI). The instrument was deployed at the South Pole in the austral summer 1999-2000, and we made observations throughout the following austral winter. We present a measurement of the CMB angular power spectrum in the range 100 < l < 900 in nine bands with fractional uncertainties in the range 10%-20% and dominated by sample variance. In this paper, we review the formalism used in the analysis, in particular the use of constraint matrices to project out contaminants such as ground and point source signals and to test for correlations with diffuse foreground templates. We find no evidence of foregrounds other than point sources in the data, and we find a maximum likelihood temperature spectral index ¼ À0:1 AE 0:2 (1 ), consistent with CMB. We detect a first peak in the power spectrum at l $ 200, in agreement with previous experiments. In addition, we detect a peak in the power spectrum at l $ 550 and power of similar magnitude at l $ 800, which are consistent with the second and third harmonic peaks predicted by adiabatic inflationary cosmological models.

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Section: Instrumentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Degree Angular Scale Interferometer First Results: A Measurement of the Cosmic Microwave Background Angular Power Spectrum

Halverson

Leitch

Pryke

et al. 2002

ApJ

Self Cite

669

331

View full text Add to dashboard Cite

show abstract

“…One is to split the broadband signal directly into smaller bands with filter banks or multiple downconverters (e.g. Padin et al 2001). The other is to use a single broad intermediate frequency (IF) band and implement a Fourier transform spectrometer, or lag correlator.…”

Section: Introductionmentioning

confidence: 99%

A 6–12 GHz analogue lag-correlator for radio interferometry

Holler¹,

Kaneko²,

Jones

et al. 2007

A&A

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Aims. We describe a 6-12 GHz analogue correlator that has been developed for use in radio interferometers. Methods. We use a lag-correlator technique to synthesis eight complex spectral channels. Two schemes were considered for sampling the cross-correlation function, using either real or complex correlations, and we developed prototypes for both of them. We opted for the "add and square" detection scheme using Schottky diodes over the more commonly used active multipliers because the stability of the device is less critical. Results. We encountered an unexpected problem, in that there were errors in the lag spacings of up to ten percent of the unit spacing. To overcome this, we developed a calibration method using astronomical sources which corrects the effects of the non-uniform sampling as well as gain error and dispersion in the correlator.

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“…Like DASI, each receiver is sensitive to only one circular polarization state and therefore the interferometer is a factor of four slower than optimum. The benefit of this scheme, however, is that the existing 10 GHz bandwidth, 13-element, correlator (Padin et al 2001) does not need to be expanded. The polarization sensitivity of the CBI expressed in units of temperature is similar to DASI's but at three times higher angular resolution, i.e., for similar integration time, the CBI should achieve roughly the same polarization sensitivity as DASI in units of ℓ(ℓ + 1)C ℓ , but at three times higher ℓ.…”

Section: Ground-basedmentioning

confidence: 99%

“…Interferometers, however, will be limited by the size of broad bandwidth correlators (the correlator scales as N 2 , where N is the number of array elements). One can conceive of scaling the DASI and CBI design (Padin et al 2001) for ∼ 100 receivers, but much larger correlators will require further advances in correlator technology.…”

Section: Future Experimentsmentioning

confidence: 99%

Status of CMB polarization measurements from DASI and other experiments

Carlstrom

Kovac

Leitch

et al. 2003

New Astronomy Reviews

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We review the current status and future plans for polarization measurements of the cosmic microwave background radiation, as well as the cosmology these measurements will address. After a long period of increasingly sensitive upper limits, the DASI experiment has detected the E -mode polarization and both the DASI and WMAP experiments have detected the TE correlation. These detections provide confirmation of the standard model of adiabatic primordial density fluctuations consistent with inflationary models. The WMAP TE correlation on large angular scales provides direct evidence of significant reionization at higher redshifts than had previously been supposed. These detections mark the beginning of a new era in CMB measurements and the rich cosmology that can be gleaned from them.

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A wideband analog correlator for microwave background observations

Cited by 19 publications

References 9 publications

Degree Angular Scale Interferometer First Results: A Measurement of the Cosmic Microwave Background Angular Power Spectrum

Degree Angular Scale Interferometer First Results: A Measurement of the Cosmic Microwave Background Angular Power Spectrum

A 6–12 GHz analogue lag-correlator for radio interferometry

Status of CMB polarization measurements from DASI and other experiments

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